# std::chrono::duration<Rep,Period>::operator++, std::chrono::duration<Rep,Period>::operator--

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< cpp‎ | chrono‎ | duration

duration& operator++(); | (1) | (since C++11) (constexpr since C++17)
duration operator++( int ); | (2) | (since C++11) (constexpr since C++17)
duration& operator--(); | (3) | (since C++11) (constexpr since C++17)
duration operator--( int ); | (4) | (since C++11) (constexpr since C++17)

Increments or decrements the number of ticks for this duration.

If `rep_` is a member variable holding the number of ticks in a duration object,

1) Equivalent to ++rep_; return *this;.
2) Equivalent to return duration(rep_++).
3) Equivalent to --rep_; return *this;.
4) Equivalent to return duration(rep_--);.

### Parameters

(none)

### Return value

1,3) A reference to this duration after modification.
2,4) A copy of the duration made before modification.

### Example

Run this code

    #include <chrono>
    #include <iostream>

    int main()
    {
        std::chrono::hours h(1);
        std::chrono::minutes m = ++h;
        m--;
        std::cout << m.count() << " minutes\n";
    }

Output:

    119 minutes

### See also

operator+=operator-=operator*=operator/=operator%= | implements compound assignment between two durations (public member function)
operator+operator-operator*operator/operator% (C++11) | implements arithmetic operations with durations as arguments (function template)

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